A 6-month-old girl is in critical condition after being detained along with a group of 21 migrants along the southern border, according to a statement released Saturday by U.S. Customs and Border Protection.

The infant and her father were apprehended by Border Patrol early Thursday in southern Texas after crossing the Rio Grande and entering the United States without authorization in a large group, CPB said.

Medical staff at the Rio Grande Valley Sector's Central Processing Center determined the child needed to be taken to a hospital. She was taken first to a local children's hospital with her father, and then by helicopter to Driscoll Children's Hospital in Corpus Christi, Texas.

CBP officers drove the infant's father more than two hours to where the infant was taken because, they said in a statement, there was not enough room for him in the helicopter.

6/27/19 5:54:14 PM -- San Luis, Arizona -- United States Border Control agents talk to a pregnant woman with her three-year old child and a 41-year-old woman with her 13-year-old daughter. They spoke no English, just enough to ask for water.(Photo: Jack Gruber, USA TODAY Network)

CBP did not identity of the father or the daughter, or indicate any details of her illness, except that she was in critical condition and continuing to receive care.

"Our thoughts and prayers are with the young girl and her father during this difficult time," CPB said in a statement.

Earlier this Last week, the Trump administration announced it was taking steps that would allow it to indefinitely detain undocumented children with their families while their immigration cases were pending.

This would override the current 20-day limit on detaining migrants with children. Department of Homeland Security officials expect that the Trump Administration effort will be challenged in federal court.

“What this will do is substantially increase our ability to end the catch and release challenges that have fueled this crisis," acting Secretary of Homeland Security Kevin McAleenan said. “No child should be a pawn in a scheme to manipulate our immigration system."

"In general, due to the short term nature of Customs and Border Protection holding, the time the vaccine takes to begin working, and the complexities of operating vaccination programs, neither CBP nor its medical contractors administer vaccinations to those in our custody," CBP said in a statement.

If migrants in detention require vaccines, they can receive them at a local medical facility, if necessary, CBP said. It is unclear whether this policy would change if the Trump administration prevails in it's attempt to detain migrant families indefinitely.